This study aims to analyze the effectiveness of the Discovery Learning model in enhancing students’ mathematical problem-solving skills among seventh-grade students at SMP Negeri 1 Sinunukan during the 2024/2025 academic year. The research employed a quasi-experimental method with a pretest–posttest control group design. The sample consisted of 40 students divided equally into two groups: an experimental group (20 students) taught using the Discovery Learning model and a control group (20 students) taught through conventional instruction. The research instrument comprised an algebraic problem-solving test administered before and after the treatment. Data were analyzed using the independent samples t-test to examine differences in posttest results between the two groups. The findings revealed a statistically significant difference in students’ mathematical problem-solving performance, with the significance value (2-tailed) = 0.000 < 0.05. This result indicates that the Discovery Learning model has a positive and substantial effect on improving students’ mathematical problem-solving abilities. Students in the experimental class demonstrated better reasoning, higher engagement, and more creative strategies in approaching algebraic problems compared to their peers in the control group. The improvement can be attributed to the model’s emphasis on student-centered exploration, hypothesis testing, and active knowledge construction, which foster deeper conceptual understanding. Consequently, Discovery Learning not only strengthens procedural fluency but also enhances students’ analytical and reflective thinking in mathematics. The study suggests that mathematics teachers adopt Discovery Learning as an alternative instructional approach to improve students’ problem-solving competence and to cultivate independent and critical learners in secondary mathematics education. Future research may expand on this study by incorporating diverse mathematical topics, larger samples, and mixed-method analyses to gain broader insights into the long-term impact of Discovery Learning on cognitive and affective learning outcomes.